1. Make a Marathon Drinking Plan
If you are doing a short run, it's a good idea to drink at least 8 oz. of water at least a half hour before going out for a run. However, if you're running a marathon, you won't be able to drink enough water beforehand to meet your needs for hydration during the event. You will have to have a plan for drinking throughout the event to avoid leg cramping and to keep your core body temperature in a comfortable and safe range.
2. Set Your Timer
Danny Dreyer, who developed the approach known as Chi Running, recommends that you carry a bottle with water and a little electrolyte mix during your marathon run. Wear a watch with a timer and set it to go off every 10 minutes. When it goes off, take a sip of water. This will ensure that your body is getting the fluids it needs, but you won't be drinking lots of water at one time, which can cause you to need to stop for a restroom break.
3. Don't Wait Until You're Thirsty
The main reason that you need a plan for drinking during a marathon is that thirst can be deceiving. By the time you are thirsty, you are approximately 3 percent dehydrated, which reduces your performance by 15 percent. In order to develop a plan, it's good to get an accurate estimate of your fluid needs. You will need to establish your sweat rate. Weigh yourself before an after and event. Every lb. of body weight you have lost is equal to 16 oz. of water. So, if you consistently lose 1 lb. of body weight during a 30-minute run, your hourly fluid needs are 32 oz.. The basis of this is average temperature; the number will be higher if it is very hot or humid. If your hourly fluid needs are 32 oz., you will have to figure out how to get that amount into your body in small increments. If you use the 10-minute sip rule, you should be drinking about 5 oz. per sip.
4. Try Some Sports Drinks
Don't stick to plain water for a marathon. In fact, experts recommend sports drinks with electrolytes for any distance that takes over an hour to run. Be sure to follow the recommendations on the label if you are making your own sports drinks. Putting too much gel in too little water can cause dehydration because it pulls fluids into the stomach to digest the carbohydrates.
5. Don't Try to Be a Camel
Some marathoners tend to overdo it by drinking too much water the day before the race. Remember that you are not a camel. If you drink too much, you risk lowering your electrolyte levels. Just drink the same amount of water that you usually do and you'll be fine.
